Electric welding



L. 1. STEELE, H. MARTIN, AND A.IE. McCARTH'Y.

ELECTRIC WELDING.

APPLICATION FILED JUNE'ZI, 1920.

. 1 410 421; Patented Mar-21,1922.

12 5HEETS-SHEET l- L. 1. STEELE, H. MARTIN, AND A. E. McCARTHY.

ELECTRIC WELDING.

APPLICATION FILED JUNE 21, 192p.

Patented Mar. 21, 1922.

12 SHEETS-SHEET 2.

ELECTRIC WELDING.

APPLICATION FlLED JUNEZI, 1920.

s m. WM m 1m wmwwo 13 m. a 2m M4 3 M M1 m P L J. STEELE, H. MARTIN, AND A. E. McCARTHY.

ELECTRIC WELDING.

APPLICATION FILED JUNE-121, I920.

1,410,421. 1 Patented Mar. 21,1922.

12 SHEETSSHEET 4.

L) J; STEELE, H. MARTIN, AND A. E. MCCARTHY.

' ELECTRIC WELDING.

APPLICATION-FILED. mu: 21, 1920.

1,410,421. 1 PatentedMar 2L1922Q 12 SHEETS-SHEET 5- Fig.5, H

L. J. STEELE, H. MARTIN, AND A E. McCARTHY.

ELECTRIC WELDING.

APPLICATION FILED JUNE 21, I920.

Patented Mar. 21, 1922.

12 SHEETS-SHEET 6- Fig.6.

L. J. STEELE, H. MARTIN, AND A. E. McCARTHY.

ELECTRH) WELDING.

APPLICATION FILED JUNE 21.1920.

12 SHEETSSHEET 7- Patented Mar. 21, 192

nil

1,&10,421.'

Attorney.

ELECTRIC WELDING.

APPLICATION FILED JUNE 21, 1920.

{M WM om S I I. mm mm 8 "m" 1 a m .M M H J M 5 P. w s

N QB n. 5 mm 3 .5. m E nNn\\ 4. H O H 8 1i 4 L L. J. STEELE, H. MARTIN, AND A. E. MCCARTHY. ELECTRTC WEEDING. APPLICATION FILED JUNE 21, 1920.

1,410,421 T l Patented Mar. 21, 1922.

12 5HEETSSHEET 9- 'L. J. STEELE, H. MARTIN, AND A. E. McCARTHY.

ELECTRIC WELDING.

APPLICATION FILED mm 21, 1920.

1,410,421. Patented Mar. 21, 1922.

FigJl.

L. J. STEELE, H. MARTIN, AND A. E. McCARTHY.

ELECTRIC WELDING. AFPHCATION HLED JUNE 21, 1920.

12 snans-snan 11.

Patented Mar. 21, 1922.

' .415 tbrrwy.

L. J. STEELE, H. MARTIN, AND A. E. McCARTHY.

" ELECTRIC WELDING.

APPLICATION FiLED juuzzr, I920.

1,410,421 Patented Mar. 21,1922.

l2 SHEETS-SHEET 1Z- Southsea, in the county of Hants,

land, and Lyonsdown, Haslemere Road,

[umTEo STATES:

PATENT oFncn.

tours .rorm s'rnmn, or ron'rsuourn, AND HAROLD MARTIN AND ANDREW nnwann m cnn'rnr, or SOUTHSEA, ENGLAND.

ELECTRIC WELDING.

Specification of Letters Patent.

Patented Mar. 21, 1922.

. Application filed June 21,1920. Serial No. 390,555.

'1 'oall whom it may concern:

Be it known that we, LOUIS JOHN STEELE, HAROLD MARTIN, and ANDREW EDWARD'MQ- CARTHY, subjects of the King of Great Britainand Ireland, residing, respectively, at H. M. Dockyard, Portsmouth, in the county of Hants, England, 15 Helena Road,

Eng-

Southsea, in the county of Hants, England,

have invented certain new and useful Improvements in or Relating to Electric Welding, of which the following is a specification.

This invention relates to a process or method of electric welding and to apparatus for use therein, the invention being 'more especially applicable for use in .the

insertion or welding of metal studs of iron, steel or brass to or into metal bodies, whether forged or cast, such as metal sheets, plates, bars, blocks, forgings and castings.

According to the present invention an electric arc is formed between the metal stud and the metallic body to which the stud is to be welded, and the said are and current are maintained for a suitable length of time, the period of which is automatically controlled, and subsequently but before interrupting the flow of the main current or welding current, the molten metal stud, end is forced through the path or direction of the are against the portion of the metal body rendered molten by the are by electrically, mechanically or pneumatically actuated means. For convenience in description the metal body to which the stud is to be welded is hereinafter referred to as the plate.

The apparatus broadly comprises two main parts, first a stud moving and arestriking mechanism which may comprise a solenoid the plunger of which is formed as or adapted foruse as a stud-holder or hasv apparatus in position.

switched onto the main circuit including In operation, the stud in the stud-holder 1s held in position against the plate, the holding-on or pot-magnets being energized at this particular time, so as to retain the Current is then the stud and plate simultaneously energizing the solenoid-coil. Immediately the solenoid? coil is energized the stud carried by the solenoid-core is withdrawn against the action of the spring (the tension of which may be adjustable) and the arc is struck'to a predetermined length which is dependent on the dimensions and setting of the springpressed. plunger in the screwed pin or plug of the stroke adjusting or setting means. On the solenoid-coil being shunted or short circuited, or open circuited or otherwise deenergized the spring returns the stud through the path or direction of the are against and preferably at right angles to the plate and with suflicient pressure to effect the welding of the stud in position on the plate. The are through the path or direction in which the stud is returned is thus maintained thoughbeing shortened until actual contacttakes place between the stud and 'The sequence of timing operations .in the latter method would be somewhat as follows. Assuming that the welding apparatus is held or fixed 1n position against the plate, the circuit through the solenoid-coil is closed thus energizing the solenoid and'overcoming the pressure of the spring so that the a stud is forced into contact with the plate. The main circuit is then closed by means of the remote controlled contactor the studholder solenoid-coil being at the same time de-energized thus enabling the spring to operate and strike the arc. The stud-holdersolenoid is then re-energized and the stud is replaced with the are still maintained. The main circuit is now broken by means of 'the contactor and. the stud-holder-solenoidcoil finally de-energized. After the final operation the stud holder obviously could not vice returning return to its original position as the result of the action of the spring until the stud holder has been disconnected from the stud which has now been welded to the plate.

ement and constructionhereinbeplacement of the stud through its arc to be varied in proportion to the size of the sole noid and the amount through the solenoid.

Further, a combination of the two aforesaid methods may be used, in which a small shunt or series solenoid would be used for striking the arc and a' larger and more powerful solenoid to return the stud and forceit into the plate or other metallic body under strong mechanical pressure. In this form a light spring would preferably be used to hold the stud in position against the of current flowing plate or other metallic body before striking the are thereby avoiding any necessity for energizing the powerful return solenoid until after'the arc has been struck and maintained and conditions are such as to enable the weld to be effected.

By means of the timing apparatus the main circuit in either arrangement may be broken immediatelyon replacement of the stud if it is desired to avoid the heavier currents which flow on replacement of the stud provided that the annealing effect of such currents is found to be unnecessary. Otherwise, the main current may be maintained after the. weld is made.

The whose sequence of operations may be controlled at the welding apparatus by means of a push button or its equivalent which on being pressed closes the circuit through a solenoid which releases a brake on the cam shaft of the timing apparatus thus permitting the cam-shaft carrying the .cams to make one complete revolution durin; which period the whole of the operations of the welding apparatus are controlled, the said welding apparatus and the timing dcto the initial position from which the sequence of operations started.

A shield may be provided for protecting the are from magnetic effects and/or air currents. This may effected by enclosing the stud-holder and are in a suitably steel. iron desired of intended for use with from, the said projectin rounded or bevelled 0 so as to facilitate The weldingend or the shoulder thereof orboth the end and shoulder of-the stud may be suitably coated with a suitable flux composition.

-The apparatus maybe of a portable or stationary nature, holding on or pots magnets being preferably provided ,when the apparatus isin its portable form and is iron or steel plates. The holding-on or pot-magnets .in other cases may be omitted, and the apparatus may be so constructed and 7 arranged that it can be supportedin position by any suitable mechanical. means .such as on a post drill or on a'radial drill or if desired by means of a'tripod and may be used in a vertical, horizontal or inclined position, means being provided to allow the position of' the operating solenoid to be tive to that of the plate in order to suit different lengths of studs.

Two or more welders or welding ap paratus constructed as hereinbefore described may be used sequentially or randomly and controlled mechanically and/or electrically from the same timing and controlling mechanism. This may be effected electrically by means of a discriminating switch which may be of the rocking magnetic type interposed in the push button circuit.

The electrical and mechanical timing and controlling mechanism hereinbefore described may be replaced by fluid controlling and timin mechanism, such mechanism being capable of operating on vacuum compressed air, oil, water or other suitable hydraulic means, operating to perform or effect the required sequence of operations part being slightly as hereinbefore set forthf In this con-' or compressed air supply piping. If desired the apparatus may be retained in position on the plate or metallic body by means of reduced pressure or vacuum apparatus.

The-apparatus may be used with direct or alternating current and the control circuits of the apparatus can be operated from a source of current supply entirely inde pendent of that of the welding current supply, such for example as a comparatively low voltage battery, or transformer supply which can be used on the main welding circuit, with a higher voltage supply on the control circuit. If a common source of supply be usedon both circuits in conjunction with the shunt solenoid operation, the arc solenoid would be directly energized when the latter is closed. If separate 'circuits be used the arc'solenoid may be energized from an auxiliary contact on the contactor which, however, may be in turn made alive by the closing of the contactor.

We will describe with reference to the accompanyin drawings, apparatus in accordance wit the present invention but we do not limit ourselves 'towthe precise arrangements and constructions .described and illustrated.

Figure 1 shows a general arrangement and wiring diagram of a portable type of apparatus.

Figure 2 is an elevation of the holding-on .apparatus or pot-magnets.

Figure 3 is a plan of Figure 2.

Figure 4 is a s1de view of Figure 3 looking in the direction of the arrow A.

Figure 5 is a vertical section on the line B, C Figure 3.

Figures 6, 7 and 8 are respectively an end elevation, a side elevation and a plan of the timing mechanism. v

Figure 9 is a wiring diagram as used with two units or welders, that is to say two complete apparatus for use by difierent oper a-' tors.

Figure 10 is an elevation of a fixed or nonportable type of apparatus. Figures 11 and 12 are respectively a sectional elevation" of the arc-striking solenoid and the wiring diagram in connection with this type of apparatus.

Figure 13 shows an alternative form of stud-holder.

Figures 14 and 15 show an elevation partly in section and a vertical section through the stud-holder of a pneumatically actuated type of apparatus. Figure 16 is an elevation partly in section of the solenoid-o erated valve for use with the apparatus 0 Figures 14 and 15, and Figure 17 is a perspective View of a preferred form of stud for use in carrying out the present invention.

Referring to Figure 1 of the drawings, 1 is the plate to which the stud 2 is to be welded. 3 is a solenoid the plunger or core 4 of which is adapted to act as a holder for the stud 2 either by forming the core end as a split conical chuck or by means of a split conical chuck capable of being removably attached to the said plunger or core 4. The solenoid 3 carrying the stud 2 is clamped in position against the plate 1 by holding-on pot-magnets 5, 6 arranged one on each side of the solenoid the coils of the said holdingon-pot-magnets being energized from any suitable source of electric energy. 7 indicates generally an automatic timing or control mechanism hereinafter fully described and comprising a cam-shaft 8, cams 9, 10,11 and 12 adapted to engage contact terminal levers of fingers 13, 14, 15 and 16 on rotation of the camshaft. The latter may be rotated by clock-work mechanism as described-with reference to Figures 6, 7 and 8; or the .said

, cam-shaft 8 may be suitably rotated electri-' c'ally. Rotation of the cam-shaft is prevented unless at the proper time by a brake 17 (Figures 6 and 8) which is released on the energization of a solenoid 18 (Figures 1, 6, 7 and 8). The positive and negativemain leads are indicated at 19, 20. 21 is a double-pole switch for connecting the zipparatus in the main circuit. Obviously the polarity of the leads 19, 20 may be reversed and in the case of .alternating current being used no definite polarity can be assumed for the apparatus main leads-22, 23. The plate 1 and the stud-holder are electrically connected thereto through positive and negative leads 22, 23 and a contactor-switch 24 electro-magnetically actuated by a solenoid 25. The positive lead 22 is connected directly to the plate 1 a suitable reactancecoil 26 and a variable resistance 27 being inserted in series in the negative lead 23 between the contactor 24 and the stud-holder. In Figure 1 the main leads and the welding circuit are shown in heavy black lines to distinguish these circuits from the other circuits of the diagram. The function of the reactance coil 26 is to delay and oppose heavy rushes of current so as to obviate sticking of the stud on the plate .due to too rapida rise in the value of the current. By means of the variable resistance 27 the value of. the main current can be controlled'or regulated to suit different sizes and material of studs and plates and other variable conditions such as temperature. The leads from the solenoid 3, .holding-on-pot magnets 5, 6 and main control switch 28 shown as a pearpush switch are collected in a common flexible cable 29 which is provided with aterminal bracket 30 having four plugswitches 31, 32,

33 and 34 adaptedto engage in plug sockets 35, 36, 37 and 38 which may be mounted on and secured to a box (not shown) carrying the timing mechanism7. The variable resistance 27, the reactance coil 26, the contactor 24 and the contactor actuating solenoid 25 may also be carried in the same box for convenience. 39 indicatesa contact terminal mounted on the box or receptacle (not shown) containing the plug sockets 35,

36, 37, and'38, reactance coil 26, variable resistance27 and timing mechanism 7, the said contact terminal 39. being employed for the closing of the circuit through the solenoid 25 operating the contactor 24. 40, 41, 42 are conveniently lamp resistances and 43 is a non-inductive resistance. The lamp 40 lights u on actuating the push switch 28 "and. is t us a convenient indicator that the timing'apparatus is in operation. The leads from the plug sockets 35, 36, 37 and 38 and the corresponding .minals 31, 32, 33

' 1 .a partof the-cables29 is shown leads from the plug terand 34 to the solenoid 3, the holding-on-pot-magnets 5 and 6 andthe .main control switch 28 are indicated for "COIIVGIHGIICB by the same reference numerals as the plug sockets themselves. In Figure dotted be low the'bracket 30 carrying the plug ter minals 31, 32, 33 and 34 so as to clearly indicate the arrangement and connection of the leads to the plug terminals andthelatter .to the plug sockets 3-5, 36, 37 and 38. The circuit through the holding-on-pot-magnets '5 and 6 may be closed by means of a switch 44, which although indicated as .a tumbler switch may be of any suitable nature. -The circuits through the main control switch 28 .and the holding-ompot-magnets are branched from the positive lead 35 as. at 45 the circuit through the solenoid-coil 3 being tapped from the lead 35 as shown at 46. The .lead 35 is electrically connected through the plug socket 35 to the cam-shaft 8 by a wire 47, the lead 36 through the socket 36 to the contact levers or fingers 13 and 14 by a wire 48 and the lead 37 through the socket 37 to the contact finger '15 by a wire 49 or by the non-inductive. resistance 43 and wire 49 to the contactor 24 and negative lead 23. The lead 38 is electrically connected through the socket 38, lead 50, lamps 41 and 42 to the common negative contact terminal 52 by the wire 51 the contact terminal 52 being connected to the common negative lead 23 by a wire 53. The circuit through the contactor actuating solenoid 25 is connected by the wire 54 from the positive lead 22 through the plug socket 35, Wire 47, camshaft 8, cam 12 thereon, contact finger 16 and wire 55 to the terminal 39 and from thence to the lead 23 by the wires 56; The circuit through the, brake releasing solenoid 18 is by way of the wire 54 from the lead 22, plug socket 35, wire 47, cam-shaft 8 of theitiming mechanism 7 cams 9 (or 10) contact finger 13 (or 14) wire 57 brake release solenoid 18, wire 58, lamp 40, wire 59, common negative terminal 52 and thence to the apparatus negative lead 23 by wire 53. The circuit through the press-button switch 28 bridges the gap between the cams 9 and 10 and the contacts 13, 14 in the circuit of the brake release solenoid 18 which gap eX-.

H5, 6 are mounted on and supported by a common vframe or carrier 60 to which is suitably. secured a-fiat metal bar .61 having an ebonite fibre or other suitable handle 62 so thatthe sole'noid-stud-holder and holding-on-pot-magnets form a single and portjablepun'it'which can be easily carried about from place to place as. desired. The studholder solenoid comprises a cover 63 Figure 5' which is secured to the carrier frame 60 by brackets '64, 65 suitably mounted on and secured to the said carrier frame. The solenoid.cover 63 is'provided with a central boss 66 onto which is screwed a cop er tube 67 surrounded by a former 68 on w ich the 'coil 69 iswound, insulating material 70 being' disposed between the former and the coil 69. The former 68-is retained in position by a disc 71 screwed to the free or outer end of the copper tube 67. The boss is provided with a central opening through which passes a in 72 adapted to carry the solenoid core or p unger 4. The coil 69 is surrounded by a steel casing 73 maintained in position in an openig in the carrier frame 60 by screws 74 Figures 3 and I4:- The upper or rear end of the pin 72 is provided with a contact terminal pin 75 having a disc 76 which is forced against the solenoid cover plate 63 by a spring 77 enclosed in an an nulus 78.-slidably disposed in an enclosing cap 79 or cover. If desired ball bearings '80 may be disposed between the adjacent end faces of the annulus 78 and the enclosing cap 79. terminal clamp 81 is suitably secured to the rear end of the contact terminal pin 75 which rear end projects beyond the enclosing cap or cover 7 9. To the latter is secured a bridge piece 82 open on opposite sides and carrying means for setting or ob- 106 *taining the correct length of stroke of. the

arc. The stroke setting means comprises a screwed plug.83 carrying a helical spring 84 in its interior, the said spring being retained in the hollow interior of the screwed plug 83 by a screwed cap 86 The inner end of the sprin 84 abuts against a slidable plunger 85 w ich is so constructed that the portion which projects from the screwed plug 83 gives the correct length of are on striking thereof. By rotating the screwed plug 83 so that the plunger 85 is just in contact with the terminal pin 75 when the apparatus is set up, for welding the correct len h of arc will subsequently be struck.

he outer end of the core 4. or plunger is provided witha split conicalchuck-to receive the stud, the respective members of the chuck being indicated at 87, 88. A suitable iron or steel disc 89 is interposed be- 126 tween the chuck and the core 4 or plunger, to reduce magnetic leakage from the core 4 in relation to the are. An alternative form of stud-holder is shewn-in Figure 13. In

B, 4 and 5 and the holding-on-pot-magnets' this construction the outer end of the core 0 4 or plunger is provided with an axial recess 90 and a transverse circular recess 91. the transverse recess is arranged a pin 92 having a squared end 93 adapted to engage in a square recess 94 formed in the wall of the core 4 and at the end of the circular recess so as to clampthe stud in the holder or core 4. The welding current may be delivered to the clamping socket 81 thus providing a central supply; or the cable carrying the Welding current may be suitably connected to the washer 89 or disc. If a central supply be employed the pin 72 is of brass and therefore it is unnecessary to have any tube such as 89 Figure 5 between the core 4 or plunger of the solenoid 3 and the adjacent casing, in which case the core 4 would be slidably fitted in the copper tube 67 as shewn in Figure 11. If, however, the welding current be delivered to and through the disc 89, the pin 72 and the said tube 89 are of suitable insulating material, so that the welding current makes alive the disc 89, the core 4 and the stud holder only. The inner end of the core 4 orplunger is of conical form and a suitable space is left between the core-end and the boss 66 on the solenoidcover 63 so as to allow for adjustment ofthe stroke and also striking of the arc.

The holding-on-pot-magnets 5, 6 are supported by the carrier frame 60 by screws 90 91' which are adjustably mounted in and insulated from the said carrier frame 60, 92;", 93- being the respective insulating bushes. The adjusting means comprise knurled nuts 94, 95, and thumb nuts 96,97. To the lower end of the screws 90' and 91 are secured cover plates 98, 99 respectively Figure 5,

which are screwed into mild steel casings 100, 101. Each of the mild steel casings is open at its lower end and surrounds a coil of wire wound on a former. 102 is the coil of the holding-on-pot-magnet 5 and 103 is the coil of pot-magnet 6. Each of the coils 102, 103 iswound on a former 104, 105 in the form of a bobbin the respective coils being separated from their formers by insulating material 106, 107. Thecover plates 98,-

99 are provided with cores 108, 109 rigid therewith and extending to and projecting beyond the outer flange of the respective formers. To the said cores are secured brass discs 110, 111 so as to retain the formers and cores in position. The cover plates 98, 99 for the pot-magnets are supportedby a brass angle frame 112 which surrounds. and guides the solenoid 3 and is insulated therefrom by an insulating bush 113. The frame 112 carrying the pot-magnets and the insulating bush 113 are slidably mounted relatively to. the casing of the solenoid 3.. 114, 115 are clam ing nuts mounted on' thescrews 90,

he coils of the pot-magnets 5, 6 and the coil of the solenoid 3 are preferably so wound. or connected as to give the same polarity at the ends of the cores adjacent the plate 1. j

The tumbler switch 44 is mounted on a bridge 'piece 116 extending between the side arms of the fiat bar 61 connected to the carrying frame 60.

The flexible cable 23 connected to the socket terminal 81 and the leads 35, 36, 37 and 38 which are collected to form a common flexible cable 29 are passed through and supported by straps 117, 118 secured to the fiat bar 61. The cable 83 is thereafter connected to the terminal socket 81 a. suitable amount of play being allowed the length of cable between the straps 117, 118 and the socket 81 to permit of the necessary movement of the stud-holder core 4 of the solenoid. The four leads 35, 36, 37 and 38 are separated from the common flexible cable 29 and thereafter cdnnected to their respective terminals. 119, 120.Figure 3 are insulating bushes for the leading-in-wires to the coils 102, 103 of the pot-magnets 5, 6'

and 121, 122 are the terminal bushes for the wires to the coil of the solenoid 3. If desired instead of or in addition to the straps 117, 118 the main cable: 23 may be which the whole sequence of operations shaft 8, cams 9, 10, 11 and 12 of which the cams 9 and 10 may be called a combination cam. The cams 9, 10 are incomplete each being formed or providedwith a gapl25, 126 respectively, and the complete set of cams 9,10, 11 they can be adjusted axially and circumferentially on the shaft 8. Relative adjustment of the two cams 9, 10 circumferentially thus alters the time periodwhich elapses between the .action of the cam 9 and the action of the cam 10. The cam 9 on rotation opens the circuit of brake release, solenoid 18 whilst the cam 10 closes the circuit of the brake release solenoid 18, independently of the remote control switch or pressbutton 28 which is inserted in parallel .therewith, so that the press-button circuit can be opened when the cam circuit 9, 10 is closed without stopping therotation of the shaft 80f the to short circuit the coil of the solenoid 3 and the cam 12 which is an evolute cam controls and 12 are mounted so that '120 timing mechanism. The cam 11 is employed the closing and openin of the main circuit energized by the lhort ail-suiting cam 11 solenoid 3 which is de- V f The switch 28 is'then operated closing the wheels,

. when the timing contact finger 16. As the before the cam 12 leaves the contact finger 16. The timing is finall adjusted by longitudinal displacement o the contact finger 16. The shaft 8 is supported in and between uprights 127, 128 and derives its motion from in the interior of which is a coiled spring'not shown andsuitable gear 130, 131, 132, 133, 134,135, 136, 137 and 138 suitably mounted on arbors carried by the uprights 127 and 128. A bracket 140 havi g horizontal arms 141, 142, supports there between a vertical shaft 143 on which is a worm 144 gearing with a worm wheel 145 or gear wheel, mounted on the arbor carrying the wheel 139. The vertical shaft 143 is provided with a collar 146. The core 147 of the brake release solenoid 18 is con nected by a bell crank lever 148 and a link b ,149 to one end of a metal strip150, the free end of whichbears against the collar 146 on the vertical shaft 143 so as to act as a brake. Suitably secured to the vertical shaft 143 as by a spring clip or other suitable means is a fan brake 151.

The method of operation is as follows, it being assumed that the holding-on-pot-magnets and the solenoid stud-holder have been placed in the desired position relatively to the plate to which'the stud is to be welded. The switch'44 is then operated so as to close the circuit through wire 35, coils of holdon-pot-magnets .6, 5, switch 44, wire 38, plug 34, plug socket 38, wire 50, lamps 42, 41 wire 51, common negative terminal 52, wire 53v and apparatus -main negative lead 23 to negative-main20.v The coils of the holdmg-on-pot-magne'tsare thus energized inde pendently of the main circuit and thestudolder and solenoid are thus retained in the desired position against the plate 1. circuit-through the brake released solenoid 18, and thereby releasing the brake member 150 from the collar 146 so'that the shaft '8- -10 comein contact with the contactfingers 13, 14 -which are normally (that is to say 7 mechanism is inoperative) over the gaps, the circuit through the push-. button switch 28 being thereby-by-passed. The circuit through the brake release solenoid 1s thus maintainedindependently of the pushbutton-circuit, which can there-fore be opened' without affecting the brake release solenoid. -There'after on further rotation of the shaft 8 the cam 12 engages the result thereof, the solenoid 25 is energized thus closing contactor 24.. The welding circuit is thus closed and current flows through the plate and stud.- Simultaneously therewith the solenoid 3 becomes energized. the stud being therefore withdrawn against the action of the suitable clockwork-mechanism comprising a barrel 129,

.comes practically de-energized.

tion of'the cam shaft 8 the cam 11 engages the contact finger 15 thereby short-circuiting or shunting the solenoid 3 which thus be- The immediate effect thereof is thatthe spring 77 returns the stud 38 through the path or direction. of the are against and preferably at right angles to the plate and with sufficient pressure to effect the welding of the stud in position on the plate. The are through the path or direction in which the stud is returned is thus maintained through being shortened until actual contact takes place between the stud and plate. On further rotation of the shaft 8 the cam 12 is disengaged from the contact finger 16 there- 'y de-energizing the solenoid 25 or opening circuit therethrough. Consequently the contactor 24 is o ened and thereby the welding circuit. am 11 on further rotation of cam shaft 8 is disengaged from contact finger 15 so that the short circuit of solenoid 3 is removed. The shaft 8 continues to rotate until the gaps in the cams 9, 1O coincide or come opposite the ends of the respective contact fingers 13, 14, thereby opening the circuit through the brake release solenoid 18. The brake-is thus applied to the timing mechanism which stops, and the cycle of operations may be repeated as often as desired by merely operating the push button switch 28.

As shown in Figure 9 two welders I), E may be employed operated by different operators so that on the pressing of either of the press button'switches 28, 28', the corresponding welder may be used, the sequence of operations being controlled by the timing nections and the timing mechanism may be such as to permit of simultaneous or sequential operations of the two welders.

In Figure 9 the parts and connections of the E welder corresponding to those of the D welder are provided with indices so as to clearly distinguish the two welders and their connections. In order to provide for the use of two Welders such as D and E the following parts apart from the additional welder are provided additional to thou shown in Figure 1. In Figure 9 the additional parts are a contractor 24', an actuating solenoid 25 therefor, a negative main apparatus lead 23', a brake release solenoid 18. two discriminating switches 152. I52

and one came -11. The timing mechanism 7 ,-brake release solenoids 18, 1 S',,-solenoids 25, 25',reactance coil 26,-variable resistance 27 ,-socket terminals 35, 36, 37, 38,and 35, 36','37', 38 are preferably arranged in one portable box, the flexible cables 29, 29, being adapted for connection to the respective set of socket terminals by the brackets 30, 30' carrying the plug switches 31 to 34, and 31' to 34'respectively. As the construction of the individual parts of the apparatus is the same as the corresponding apparatus of Figurel it is proposed to describe the welding operation as effected by the welder E the circuits-of thewelder D being clearly shown and the operation being the same as the welder of Figure 1. Referring to the welder E the welding circuit is from the positive main 19, switch 21 appa ratus main positive lead 22, plate 1, stud 2', lead 23, contactor 24', variable resistance 27, reactance coil 26, apparatus main negative lead 23 to negative main 20 by switch 21. The shunt solenoid circuit is from positive main 19, switch 21, wire 22, wire 54, wire 153, socket 37', plug 33', wire37' in flexible cable 29', wire.46' solenoid 3, wire 38', plug 34', plug socket 38', 'wire 154',

non-inductive resistance 43, wire 155,"auxiliary contacts 156, 157" of contactor -24',

wire 158 to negative 23 and thence to main negative 20., On pressing the push button switch 28 the circuit through the brake release solenoid 18 is closed through wire 37 (Figure 9), push 28', plug 32, socket 36', wire 159', wire 160', contacts 161, 162' of discriminating switch 152, wire 163 brake release solenoid 18', wire 164, lamp 165, wire 158 and negative main 23. Solenoid 18' is tlllgS energized and the brake 160 of the timing mechanism 7 is released and the cam shaft 8 begins to rotate. The energization of solenoid 18' opens the circuit through contacts 161, 162 and plunger of solenoid 18' which plunger then closes on contacts 168, 169. 166 and 167 are resistance'lamps hav-' ing independent connection to the terminal sockets 35 and 35 respectively as shown in Figure 9. The cores of the brake releasing solenoids 18 18- are normally, when the solenoids are not energized, maintained against stopsin the up or inoperative position. The opening of contacts 161, 162 opens the circuit through solenoid 18 and the closing of contacts 168, 169 closes the gap in the solenoidcircuit 25' so as to allow of the said solenoid 25' being energized at the proper time through the timing mechanism 7. The timing mechanism is connected to the respective solenoids 25,..25' which actuate the contactors 24, 24' through the gaps in the"discriminating switchesf1'52, 152'. As soon as the timing mechanism begins to rotate andIthe cams 9 and l0come into contact with the contact fingers 13, 14

plate'and stud and the solenoid 3' is ener- I gized, thereby withdrawing stud against spring action from contact with the plate and striking of the'arc is thus effected. On

further rotation of the camshaft 8 cam 11 engages finger 15 thereby short circuiting or shunting solenoid 3 which thus becomes de-energized, so that the spring returns the stud through the path or direction ofthe are against and preferably at right angles to the" plate and with sufficient pressure to effect th welding of the stud in position on the plate. The are through the path or direction in which the stud is returned is thus .maintained through being shortened until actual contact takes place between the stud and plate. Further rotation of the cam shaft 8 causes cam 12 to become disengaged from the contact finger 16 thereby de-energizing and consequently opening the circuit through thesolenoid 25'. Consequently contactor switch 24 opens and main welding circuit is broken. Thereafter cam 11 clears contact finger 15', thus. removing the short circuit tosolenoid 3. The cam shaft 8 continues to rotate until the gaps in cams 9 and 10 coincide with the ends of contact fingers '13, 14. The circuit through brake release solenoid 18' is therefore opened and the brake is applied to the timing mechanism 7 so that rotation of the cam shaft 8 ceases, whilst at the same time, the contacts 168, 169 are opened and the contacts 161 and 162 are closed through the plunger of the brake release solenoid 18. Incidentally the lamp resistance 165 lights up and indicates when current flows through the solenoids 18 or 18'.

Figure 10 shows an arrangement wherein the apparatus is stationary, the solenoid 3 in this arrangement being carried by the spindle of a post drill 170. 171 is the drill spindle, 172 the table or support for the piece 173 to which the stud 2' is to be welded and 3 as before is the solenoid stud-holder. In this construction and arrangement the holding-on-pot-magnet's' 5, 6 are omitted and the solenoid 3 is supported in position on the slidablespindle 171-by a clamping member formed of half hoop metal straps'174 may be clamped in any desired position thereon by the clamping handle 177. 17 8 is projectingfrom the spindle 171. The table brake is released the shaft 8 as above stated is carried in 10 to effect satisfactory welds a hand wheel operatingmember which on rotation causes the spindle 171 to ascend or descend as required, the said spindle being suitably geared to the hand. wheel shaft. Sudden or abrupt release of the spindle 171 may be efi'ected by gear 179, and handle 181 of any well'known construction. shown in Figure 10 the timing mechanism a portable, box l82'the necessary flexible cables to the solenoid '3. The said cables are preferably supported in a clamping bracket 185 i on' the standard or post 170'. The interior construction of the solenoid 3 is practically the same as that described withreference to Figures 1, 2, 3, 4 and 5, and it is thought that further description thereof is unnecessary. The circuit through the solenoid 3 for the constructionshown in Figure 10 is shown in Figure 12.

It has been. found that with certain sizes and qualities of studs and the like, mechanical pressure is required upon replacement of the stud on the plate in order and the fluid con trolling and actuating mechanism shown in Figures 14, 15 and 16 may be employed with this end in view and/or as a substitute apparatus for the electrical and mechanical apparatus and mechanism, hereinbefore described. Inthe construction and arrangement therein shewn the stud-holdei chuck is mounted on the end'of a rod 186 carrying a piston 187 arranged to reciprocate under the action of compressed air in a hollow cylinder 188. The cylinder 188 may be of a portable nature or may be provided with means such as metal straps 189, 190 for connecting the cylinder to and supporting the latter from a stationary object. Thecylinder 188' is coupled by suitably shaped tubes its interior with-two disc-valves 194, mounted on a common rod1-96 and adapted to be displaced inopposite directions by the action of a solenoid hereinafter described.

The cylinder 188 is provided with ports 198, 199 through which compressed air is admitted to the respective sides ofthe piston 187, the' spent air also exhaustlng through the said orts, pipes 191, i192 and o posite. ends of t e rod 196 to the atmosp ere. The rod 196 is hollow at each end and is provided with through way openings 200, 201 which at the proper time effect communicationbetween the pipes 191, 192 and the atmosphere through 203 in the res ective end of the 'rod 196. The rod 196 an the valves'194, 195 are actuated by a solenoid 204, the core 205 of which is coupled'to the'rod 196 by links 206,207,

208 the link 207 being pivotally supported by an arm 209 suitably securedto the valve caslngml93. 209' is the terminal socket for attac ent'of the main circuit cable to the 183, 184 being led therefrom a a heavy 191', 192 -to a valve casing-193 provided in stud-holder which in this case is fixed to the rod 186. The solenoid 204 is carried by and clamped to the valve casing 193 b straps 210, 211, andvthe core 205 of the solenoid is actuated against'theaction of a a passage 213 therein which can be place in communication with an air inlet 214, or

alternatively with the atmosphere at 215. The air supply pipe which is preferably of the flexible type is connected to the port 214; or the port 215 may be connected to the air spring 212. 197 is a two-way valve having supply pipe and the port 214 with the at position shown is de-energized so that the rod 196' is also in the position shown, the piston 187 being therefore forced in the direction of the plate so that the stud comes intocontact with the plate;

' The welding circuit through the stud and plate by way of the terminal 209 is closed and the solenoid 204 is energized simultaneousl therewith, preferably from an indepen ent source of supply. The result is that therod 196 is moved' through the links 206, 207, 208 by the core 205 of the solenoid so that the valve 194 closes on its seat and the valve 195 thus opens. At the same time compressed air admitted through the valve 197'flows by underside of-the piston 187. As the. rod 196 moves downwards to the closing position of the valve.194 on its seat, the -compressed air on the upperside of the piston is suddenly released and escapes through the tube 191, openings 200 and-"passage 202 to the atmosphere." The piston 187 rod-1'86 and stud is thus withdrawn from the plate and the arc is struck. On the de-energization or short-circuiting of the 196 is moved upward by the action of the -s ring 212, and compressed air is admitted underside of the piston has now been rethe valve 195,pipe 192 to the solenoid .204 the rod' lieved the stud is returned through the path 'or direction of the are a ainst and prefer- :abl at right angles to th the stud in position on the'plate. The are stud is'returnedvis thus maintained through e plate and with su cient pressure to efiect the welding of being shortened until actual contact takes. 7

placebetween the stud and plate. Thereafter the'main circuit or welding current is "opened and the cycle of operations is re peated as often as desired. It should be understood that the movement of the valve 197 the energlzation and de-energization of the solenoid 204 and the opening and closing 

